Various optical systems have been proposed as an optical system assembled with a virtual image display apparatus such as a head-mounted display (hereinafter referred to as HMD) mounted on a head portion of an observer. Particularly, various prisms have been proposed as light guide prisms arranged in front of an eye (for example, refer to PTL 1, 2, and the like).
With regard to the virtual image display apparatus such as the HMD, it is desired to accelerate a reduction in size and weight and to achieve a wide angle of view without deteriorating image quality. Also, in a state where only image light is viewed with an entire field of vision of the observer being covered, the observer cannot determine a state of an outside world to be nervous. Meanwhile, with see-through view in which the outside world and the image are shown in an overlapped manner, various novel applications of virtual reality are generated. Accordingly, display expressing the image light overlapped without hindering the field of vision of the outside world is desired.
Allowing for the above-described situation, a light guide device is configured, for example, by a penetration-type prism arranged in a see-through manner in front of the eye of the observer with a plurality of free-form surfaces such that the observer can have a better feeling of mounting similar to a shape of glasses while a form of an appearance can be excellent. In a case of the light guide device applied to the virtual image display device with a see-through function, an inclined semi-transmissive surface is disposed on one end of a block-shaped light guide prism so as to overlap, for example, external light with the image light. In this case, in order to complement the inclination of the semi-transmissive surface and cover the front of the eye uniformly, another block-shaped light-transmitting member (opposing prism) that forms a pair is required to be bonded. During the bonding, acceptable see-through performance and image formation are not ensured if, for example, bubbles enter a bonding site and a distortion is generated on a reflection surface. Accordingly, it is important to appropriately control, for example, a flow direction of the adhesive during adhesion for the bonding and to have an excellent adhesive filling state.